Propeller-wheel.



J. s. BENSON.

PROPELLBR WHEEL. APPLICATION FILED snrLls, 1969.

981,835, Patented Jan. 17,1911.

, Jwzya j wazzf v abtowuao UNITE JOSEPH S. BENSON, OF IOWA CITY, IOWA.

PROFELLER-WHEEL.

Specification of Letters Patent.

Patented Jan. 17, 1911.

Application filed September 13, 1909. Serial No. 517,384.

To all whom it may concern:

Be it known that I, JOSEPH S. BENSON, a citizen of the United States,residing at Iowa City, in the county of Johnson and State of Iowa, haveinvented a new and useful Propeller-Wheel, of which the following is aspecification.

My invention relates to propellers and has for an object to obviate asmuch as possible the drag resulting from negative pressure exerted bythe water upon the leading portions of the propeller blades whichexperiment and calculation has shown to be very considerable and alsodoubly wasteful in that it wastes not only the power required to produceit, but also sufficient power to produce an amount of thrust equal tocounteracting its detrimental effect, For this purpose the forward orleading portion of each blade is terminated adjacent the leading edge ofthe arm while the following portion is elongated and curved downward soas to terminate farther from the hub than the leading edge whereby thewater escaping from the leading portion of the blade due to thecentrifugal force developed when the wheel is rotated is caught andutilized to force forward the boat.

It has been demonstrated by experiment that the blades of largepropeller wheels as usually fitted, reach out into comparativelyundisturbed water while small propeller wheels have a tendency to racedue to the occasional failure of the water to flow in behind the buttocklines. It has been further determined by calculation that the surfacefrictional resistance commonly known as skin friction varies per squarefoot of areaspace directly as the distance from the center of the hub sothat any increase in diameter means large increase in the amount ofpower absorbed in overcoming this friction.

My present invention spaces the blades well out from the hub so thatthey will reach out into comparatively undisturbed water, the spacingarms being inclined toward the rear end face of the hub and arrangednonradial on the hub so as to utilize the Water currents intermediatethe blades and the hub instead of simply churning the water as inpropellers of this character previously constructed.

The invention further provides a propeller of considerable diameter butwith the greatest area so positioned relatively with the hub as tocounter-balance the mischievous effect of the skin friction.

With the above advantages and other objects in view which willappear asthe nature of my invention is better understood, my invention embracesthe novel details of construction and combination of parts illustratedin the accompanying drawings, shown in the following specification, andset forth in the appended claims.

In the accompanying drawing,Figure 1 is a perspective view of myimproved propeller wheel with the blades shown in side elevation. Fig. 2is a side elevation of the propeller. Fig. 3 is a plan view of the same.Figs. 4, 5 and 6 are vertical sections, taken on the lines AA, B--B,G-C, respectively of Fig. 3. Fig. 7 is an enlarged transverse section ofan arm taken on the line D-D of Fig. 1. Fig. 8 is a similar view, takenon the line E-E of Fig. 1. Fig. 9 is a fragmentary view in end elevationof a propeller blade.

Like characters of reference designate similar parts in the views shown.

Referring now to the drawing, a propeller wheel is shown having a hub 1adapted to be secured to any desirable construction of pro peller shaftapplicable for the particular style of boat or vessel to which mypropeller is applied. Projecting outwardly from the hub are arms 2disposed in a plane intersecting at an angle of about 30 degrees to thelongitudinal diameter of the hub and each formed with a twist whichrolls from the root 8 to the extremity 4 of the arm, the curves of thetwist at the root 3 being coarser, that is to say, of greater radiusthan the curves at the extremity 4: which feature is best shown in Figs.7 and 8. The strength of the arm at the root varies directly as thebreadth of the arm thereat, so that, by forming the root of the arm witha twist, a greater length of root and therefore a greater hold on thehub is obtainable than with the approximately straight or untwisted armemployed in similar propellers as now constructed.

The arms are thickened at their intermediate portions 5, thence taper tothe leading edge 6 and following edge 7, the particular advantage ofthis structure being to decrease the dead weight of the propeller and,therefore, a corresponding amount of ower absorbed in overcoming thefriction on the shaft bearings and also to expose a curved surface fromthe leading edge to where the arm is thickest so that. not. only willthere be a less negatlve pressure on the leading portions of thearinthan usual, but also what negatlve pressure there may be. will beexerted at a less detrlmental angle.

than in a similarly arranged blade of uniform thickness. Each armprojects nonradially from the hub in order to position its'flukeor bladeSin apeculiar' relation to the hub l, hereinafter described. Each-armgreater horizontal distance from' the stern ofthe'boat' than the rootsof the arms. The

drivingportions of theblades thus engage the water flowingrearwardlyfromthebuttock lines ofthe boat a second later'than wouldblades standing perpendicular to the hub and minimize the tendency ofthe pro peller to race, due to the occasional failure ofthe water toflow in close behind the'but-= tock lines of the boat.

Positioned at the extremities of the arms are propeller blades 8, eachof which is arcuate in contour and of uniform width: from the leadingedge 9'to the following edge 10. Each blade is connectedto its arm atapoint forward of the median vertical diameter in order that theleadingedge 9' of the blade will terminate adjacent the leading edge 6of the arm 2. In practice it is found that when a screw propeller is ofsufficient diameter and of ample area, any addition to the leading edgeof the blade will act as a drag and seriously reduce the eliiciency ofthe blade. By terminatingthe leading edge of the blade adjacent theleading edge of the arm, as above described, the disadvantage of thedrag found in the centrally mounted propeller blades is entirelyobviated; By this novel'manner of mounting the blades, namely,connecting. each are shaped blade at a point adjacent its leading edgeto the extremities of the inclined arms, the following edge 10 of eachblade is spaced a considerably greater distance from the longitudinalcenter of the hub than the leading edge 9. This feature is best shown inFig. 9. The particular advantage in the following edge being spacedfarther from the hub than the leading edge is that as the blade isrotated in the direction of the arrow heads, the water thrown upwardfrom the leading portions of the blade by centrifugal force will becaught by the following portions of the blade and utilized in further.propelling the boat forward insteadof being dissipated as in the usualform of. centrally -mounted' propeller blades.

Each propeller blade is. bent or' rolled from its intermediate portion11' towardthe following edge and also bent or rolled for- .wardlytherefrom toward the leading edge, so that. the following. edge 10 isinclined at an opposite angle to a plane passed through the-longitudinaldiameter of the blade, than .the leading edge 9 to the same plane. Thismay be seen by reference to Figs. stand 6 in which the dotted linerepresents a plane passing through the longitudinal diameter 'o-ftheblade, perpendicular to the axis of the hub. This construction producesa curved channel longitudinally of theblade which permits of an easypassage of the water toward the rear of the blade but causing'the sameat every point in its passage to'be'ac- .celerated and toforce'forwardthe boat to a much greater extent than would be possible.in. a; flat blade from X which the water escapes from the extremities'of the blade without imparting its full latent driving capacity thereto.

Each blade isdisposed diagonally the hub,.as may be seen by referring toFig. 3-

andat a different angle tothe longitudinal idiameter of the hub than itscorresponding arm, the preferable relation'of the parts beling todispose the-arm at an angleof ap-- proximately 30 degrees from thelongitudi nal diameter-50f the hubyand'the blade at aplproximately anangle of 60 degrees from said'diameter as shown in Fig. 3. -Each armiispreferably widened at its upper-end, as

.shown at 12, so that the great length'of the joint between the bladeand arm willgive a isufiicient rigidity to the blade to prevent an?abnormal amount of vibration of the parts iwhen the wheel is rotated.The arms being Ewidest at the portion remote from thehub .serve toimpart a considerable driving capacity to the arms as-the flared endswill be extended out into the comparatively undisgturbed water while theportion nearest the ihub which in'the ordinary propeller'simply fchurns=the water, is thickened and contracted in breadth wherebythe skinfrictionis reduced and the root portion of the arms utilized simply ingiving additional strength and stability to-the blades.

It will be noted that the thicknessof the bladeis greatest at itsintermediate portion and tapersuniformly to thelateralextremi ties l3and 14 and to theleading and following edges of the blade. The advantageof this construction is that the negative pressure exerted by thestreams orcur-rents of water upon the leading portions of the blade willbe directed from'the curved vout'ersurface of the-blade with a lessappreciable mischievous effect than in a blade of uniform thickness.

From the foregoing description, taken in connection with theaccompanying drawings, it is thought that the construction and operationof my invention will be easily understood without a more extendedexplanation, it being understood that various changes in the form,proportion and minor details of construction may be made withoutsacrificing any of the advantages or dearting from the spirit of theinvention.

That is claimed is 1. In a propeller wheel, a hub, arms projecting fromthe hub, said arms being set obliquely to the longitudinal diameter ofthe hub and being inclined toward the rear end face of the hub, andblades secured across the extremities of the arms, the leading edges ofthe blades being spaced a less distance from the hub than theirfollowing edges.

2. In a propeller wheel, a hub, nonradial arms projecting from the hub,said arms being inclined toward the rear end face of the hub, and curvedblades secured across the extremities of the arms, the leading edges ofthe blades being spaced a less distance from the hub than theirfollowing edges.

3. In a propeller wheel, a hub, nonradial arms projecting from the hub,said arms being set obliquely to the longitudinal diameter of the huband being inclined toward the rear end face of the hub, and arcuateblades secured across the extremities of the arms, the leading edges ofthe blades being spaced a less distance from the hub than theirfollowing edges.

4;. In a propeller wheel, a hub, arms projecting from said hub, saidarms inclining toward the rear end face of the hub, and arcuate bladessecured adjacent their leading edges to the extremities of said arms,said blades being of uniform width and tapering in thickness from thecenter to each lateral edge and from the center to the leading edge andto following edge, said blades having a longitudinal twist adapted toper- I mit an easy passage of the water toward the rear of the blade.

In a propeller wheel, a hub, arms projecting from said hub, said armsinclining toward the rear flat end of the hub and having a longitudinaltwist rolling from end to end of the arm, and arcuate blades securedadjacent one end to the extremities of said arms.

6. In a propeller wheel, a hub, nonradial arms inclining rearwardly fromsaid hub, each of said arms having a longitudi nal twist rolling fromthe root to the extremity of the arm, said arms being thick- &

est at their intermediate portions and gradually tapering from thence totheir leading and following portions, and arcuate blades secured to theextremities of said arms and having their leading edges spaced a lessdistance from said hub than their following edges.

7. In a propeller wheel, a hub, non-radial arms projecting rearwardlyfrom said hub, said arms being flared from their roots to theirextremities and having a longitudinal twist rolling from their roots totheir extremities, and propeller blades secured adjacenttheir leadingedges to the flared extremities of said arms, said propeller bladeshaving their following edges oppositely inclined to their leading edgesand the intermediate portions thickened and gradually tapering fromlateral edge to lateral edgeand from leading edge to the following edge.

8. In a propeller wheel, a hub, non-radial arms rigidly secured to saidhub, said arms being set diagonal to the longitudinal diameter of saidhub and sloping toward the rear end face of the hub, said arms eachhaving a longitudinal twist greater in pitch at the secured end andgradually decreasing from thence to the free end, and curved propellerblades secured at one end to said arms, said propeller blades beingdisposed at a lesser angle in relation to the longitudinal diameter ofsaid hub than said arms.

9. In a propeller wheel, a hub, non-radial arms projecting rearwardlyfrom said hub, said arms being flared from their secured ends to theirfree ends, said arms each having a longitudinal twist graduallydecreasing in pitch from their secured ends to their free ends, curvedpropeller blades rigidly secured to the flared extremities of said armsand rolled forwardly from the secured portion and backward therefrom soas to present the leading edges and following edges at opposite anglesto the plane of said arms, said propeller blades having their followingedges spaced a greater distance from said hub than the leading edges.

In testimony that I claim the foregoing as my own, I have hereto affixedmy signature in the presence of two witnesses.

JOSEPH S. BENSON.

\Vitnesses P. A. KoRArI, W. J. IVEEBER.

